Fahad H. Ahmad (+92 323 509 4443)
9701 CHEMISTRY MCQs
Moles &
Stoichiometry
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AS: Moles and Stoichiometry (MCQs)
Page 1
Fahad H. Ahmad (+92 323 509 4443)
AS: Moles and Stoichiometry (MCQs)
6
Use of the Data Booklet is relevant to this question.
In some countries, anhydrous calcium chloride is used as a drying agent to reduce dampness in
houses. The anhydrous salt absorbs enough water to form the dihydrate CaCl2.2H20.
What is the percentage increase in mass?
A
B
14%
24%
C
32%
D
36%
w/14/qp13
8
Use of the Data Booklet is relevant to this question.
Ferrochrome is an alloy of iron and chromium. Ferrochrome can be dissolved in dilute sulfuric
acid to produce a mixture of FeS04 and Cr2(S04)3. The FeS04 reacts with K2Cr207 in acid
solution according to the following equation.
When 1.00 g of ferrochrome is dissolved in dilute sulfuric acid, and the resulting solution titrated,
13.1 cm3 of 0.100 mol dm-3 K2Cr207 is required for complete reaction.
What is the percentage by mass of Fe in the sample of ferrochrome?
A
1.22
B
4.39
C
12.2
D
43.9
w/14/qp13
29 Which equation correctly represents the balanced equation for the complete combustion of a
hydrocarbon with the formula CxHy?
A
y
CxHy + (x + - )02
2
y
> xC02 + -H20
2
B
y
CxHy + (x + -)02
4
> xC02 + yH20
c
y
y
CxHy + (x + -)02 -> xC02 + -H20
4
4
D
CxHy + (x +
1- )02
4
y
� xC02 + -H20
2
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Fahad H. Ahmad (+92 323 509 4443)
6
Aluminium carbide, Al4C3, reacts readily with aqueous sodium hydroxide. The two products of the
reaction are NaAl02 and a hydrocarbon. Water molecules are also involved as reactants.
What is the formula of the hydrocarbon?
w/14/qp11
15 Use of the Data Booklet is relevant to this question.
A sample of potassium oxide, K20, is dissolved in 250 cm3 of distilled water. 25.0 cm3 of this
solution is titrated against sulfuric acid of concentration 2.00 mol dm...J. 15.0 cm3 of this sulfuric
acid is needed for complete neutralisation.
Which mass of potassium oxide was originally dissolved in 250cm3 of distilled water?
A
2.839
B
28.39
C
47.1 g
D
56.69
w/14/qp11
3
A 10cm3 sample of 0.30moldm-3 Tl•No3- required 20cm3 of o.tornotdm? acidified NHN03 to
oxidise it to Tl3• in solution. Vanadium is the only element reduced in this reaction.
What is the oxidation number of the vanadium in the reduced form?
A
+1
B
+2
C
+3
D
+4
w/13/qp13
12 Use of the Data Booklet is relevant to this question.
The reaction between aluminium powder and anhydrous barium nitrate is used as the propellant
in some fireworks. The reaction produces the metal oxides and nitrogen.
Which mass of barium oxide is produced when 5.409 of aluminium powder reacts with an excess
of anhydrous barium nitrate?
A
1.629
B
3.069
C
9.189
D
10.29
w/13/qp13
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Fahad H. Ahmad (+92 323 509 4443)
8
Use of the Data Booklet is relevant to this question.
The approximate percentage composition of the atmosphere on four different planets is given in
the table below.
The density of a gas may be defined as the mass of 1 dm3 of the gas measured at s.t.p.
Which mixture of gases has the greatest density?
planet
major gases I
% by number of molecules
A
Jupiter
H2 89.8, He 10.2
B
Neptune
H280.0, He 19.0, CH41.0
c
Saturn
H2 96.3, He 3.25, CH4 0.45
D
Uranus
H282.5, He15.2, CH42.3
w/13/qp11
10 Use of the Data Booklet is relevant to this question.
Which sodium compound contains 74.2% by mass of sodium?
A
sodium carbonate
B
sodium chloride
C
sodium hydroxide
w/13/qp11
17 Use of the Data Booklet is relevant to this question.
In an experiment, 0.6 mol of chlorine gas, CZ2, is reacted with an excess of hot aqueous sodium
hydroxide. One of the products is a compound of sodium, oxygen and chlorine.
Which mass of th is product is formed?
A
21.39
B
44.?g
C
63.99
D
1289
s/14/qp13
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Fahad H. Ahmad (+92 323 509 4443)
9
Use of the Data Booklet is relevant to this question.
In an experiment, 12.0dm3 of oxygen, measured under room conditions, is used to burn
completely 0.10 mol of propan-1-ol.
What is the final volume of gas, measured under room conditions?
7.20dm3
A
B
8.40dm3
C
16.8dm3
D
18.00dm3
s/14/qp12
14 Ammonium sulfate in the soil is slowly oxidised by air, producing sulfuric acid, nitric acid and
water as the only products.
How many moles of oxygen gas are needed for the complete oxidation of one mole of ammonium
sulfate?
A
1
B
2
C
3
D
4
s/14/qp12
19 Use of the Data Booklet is relevant to this question.
In an experiment, 0.125 mol of chlorine gas, Cl 2, is reacted with an excess of cold aqueous
sodium hydroxide. One of the products is a compound of sodium, oxygen, and chlorine.
Which mass of this product is formed?
A
9.31 g
B
13.3g
C
18.6g
D
26.6g
s/14/qp12
40 Use of the Data Booklet is relevant to this question.
In an organic synthesis, a 62% yield of product is achieved.
Which conversions are consistent with this information?
1
74.00g of butan-2-ol � 44.64g of butanone
2
74.00g of butan-1-ol � 54.56g of butanoic acid
3
74.00g of 2-methylpropan-1-ol � 54.56g of 2-methylpropanoic acid
s/14/qp11
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Fahad H. Ahmad (+92 323 509 4443)
18 Use of the Data Booklet is relevant to this question.
A chemist took 2.00 dm3 of nitrogen gas, measured under room conditions, and reacted it with a
large volume of hydrogen gas, in order to produce ammonia. Only 15.0% of the nitrogen gas
reacted to produce ammonia.
What mass of ammonia was formed?
A
0.2139
B
0.4259
C
1.42g
D
2.83g
s/14/qp11
10 Use of the Data Booklet is relevant to this question.
A washing powder contains sodium hydrogencarbonate, NaHC03, as one of the ingredients. In a
titration, a solution containing 1.00g of washing powder requires 7.15cm3 of 0.100moldm-3
sulfuric acid for complete reaction. The sodium hydrogencarbonate is the only ingredient that
reacts with the acid.
What is the percentage by mass of sodium hydrogencarbonate in the washing powder?
A
3.0
B
6.0
C
12.0
D
24.0
s/13/qp13
12 Use of the Data Booklet is relevant to this question.
Anhydrous magnesium nitrate, Mg(N03)2• will decompose when heated, giving a white solid and
a mixture of two gases X and Y.
Y is oxygen.
What is the ratio mass of X released ?
mass of Y released
1
1_
A _
B __
0.174
0.267
c
1_
_
0.348
D
__
1
3.43
s/13/qp13
18 In a famous experiment, Wohler heated 'inorganic' ammonium cyanate in the absence of air. The
only product of the reaction was 'organic' urea, CO(NH2)2. No other products were formed in the
reaction.
What is the formula of the cyanate ion present in ammonium cyanate?
A
CNO-
B
CN02-
c co-
D
No-
s/13/qp13
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Fahad H. Ahmad (+92 323 509 4443)
27 Use of the Data Booklet is relevant to this question.
Which volume of oxygen, at room temperature and pressure, is needed for complete combustion
of 0.1 mol of ethanol?
7.2dm3
A
B
8.4dm3
C
14.4dm3
16.8dm3
D
s/13/qp13
13 Use of the Data Booklet is relevant to this question.
Magnesium nitrate, Mg(N03)2, will decompose when heated to give a white solid and a mixture of
gases. One of the gases released is oxygen.
29. 7 g of anhydrous magnesium nitrate is heated until no further reaction takes place.
What mass of oxygen is produced?
A
3.2g
B
6.4g
C
12.8g
D
19.2g
s/13/qp12
26 Use of the Data Booklet is relevant to this question.
Which volume of oxygen measured at room temperature and pressure is needed for complete
combustion of 0.1 mol of propan-1-ol?
A
10.8dm3
B
12.0dm3
C
21.6dm3
D
24.0dm3
s/13/qp12
2
A mixture of 10 cm3 of methane and 10 cm3 of ethane was sparked with an excess of oxygen.
After cooling to room temperature, the residual gas was passed through aqueous potassium
hydroxide.
All gas volumes were measured at the same temperature and pressure.
What volume of gas was absorbed by the alkali?
A
15cm3
B
20cm3
C
30cm3
D
40cm3
s/13/qp11
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Fahad H. Ahmad (+92 323 509 4443)
11 A solution of Sn2• ions will reduce an acidified solution of Mn04- ions to Mn2• ions. The Sn2• ions
are oxidised to Sn4• ions in this reaction.
How many moles of Mn2• ions are formed when a solution containing 9.5 g of SnCZ2 (M,: 190) is
added to an excess of acidified KMn04 solution?
A
0.010
B
0.020
C
0.050
D
0.125
s/13/qp11
16 Use of the Data Booklet is relevant to this question.
Magnesium nitrate, Mg(N03)2, will decompose when heated to give a white solid and a mixture of
gases. One of the gases released is an oxide of nitrogen, X.
7.4g of anhydrous magnesium nitrate is heated until no further reaction takes place.
What mass of X is produced?
A
1.5g
B
2.3g
C
3.0g
D
4.6g
s/13/qp11
26 Use of the Data Booklet is relevant to this question.
2.30 g of ethanol were mixed with an excess of aqueous acidified potassium dichromate(VI). The
reaction mixture was then boiled under reflux for one hour. The desired organic product was then
collected by distillation. The yield of product was 60.0%.
What mass of product was collected?
A
1.329
B
1.389
C
1.809
D
3.209
s/13/qp11
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Fahad H. Ahmad (+92 323 509 4443)
34 An element X and compound YZ react separately with acid as shown.
X(s) + 2H\aq) � x2•(aq) + �(g)
YZ(s) + 2H.(aq) �
v •(aq) + H2Z(g)
2
When 1.0 g of either X or yz is reacted with an excess of acid, the total volume of gas formed is:
the same.
Which statements are correct?
1
A�X) = M,(YZ)
2
X and Y are metals.
3
X and Y must both be in the same Group of the Periodic Table.
w/12/qp13
25 Use of the Data Booklet is relevant to this question.
2.30 g of ethanol were mixed with aqueous acidified potassium dichromate(VI) and the desired
organic product was collected by immediate distillation under gentle warming. The yield of
product was 70.0%.
What mass of product was collected?
A
1.549
B
1.61 g
C
2.109
D
2.209
w/12/qp13
9
During steel-making the impurity P4010 is removed by reacting it with calcium oxide. The only
product of this reaction is the salt calcium phosphate, Ca3(P04)2•
In this reaction, how many moles of calcium oxide read with one mole of P4010?
A
1
B
1.5
C
3
D
6
w/12/qp13
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Fahad H. Ahmad (+92 323 509 4443)
17 Use of the Data Booklet is relevant to this question.
1.15 g of a metallic element reacts with 300 cm3 of oxygen at 298 K and 1 atm pressure, to form
an oxide which contains 02- ions.
What could be the identity of the metal?
A
calcium
B
magnesium
C
potassium
D
sodium
w/12/qp11
15 Use of the Data Booklet is relevant to this question.
The nitrates of beryllium, calcium, magnesium, and strontium all decompose in the same way
when heated. When 2.00 g of one of these anhydrous nitrates is decomposed, 1.32 g of gas is
produced.
What is the nitrate?
A
beryllium nitrate
B
calcium nitrate
C
magnesium nitrate
D
strontium nitrate
w/12/qp11
26 Use of the Data Booklet is relevant to this question.
2.30 g of ethanol were mixed with aqueous acidified potassium dichromate(VI). The desired
product was collected by immediate distillation under gentle warming.
The yield of product was 70.0%.
What mass of product was collected?
A
1.549
B
1.61 g
C
2.109
D
3.149
w/11/qp12
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Page 10
Fahad H. Ahmad (+92 323 509 4443)
4
Use of the Data Booklet is relevant to this question.
560 kg of nitrogen and 120 kg of hydrogen are pressurised, heated and passed over an iron
catalyst. When the mixture of gases reaches equilibrium, it contains 96 kg of hydrogen.
Which mass of ammonia does it contain?
A
24kg
B
68kg
C
136kg
D
680kg
w/11/qp12
2
The following equations the letters W, X, Y and Z all represent whole numbers.
When correctly balanced, which equation requires one of letters W, X, Y or Z to be 5?
A
WCJH1COOH + X02 � YCOi + ZH20
B
WC4Ha + XOi � YCOi + ZH20
C
WH3P04 + XNaOH � YNa2HP04 + ZH20
D
WNH3 + X02 � YN2 + ZHiO
w/11/qp12
25
Use of the Data Booklet is relevant to this question.
2.76 g of ethanol were mixed with an excess of aqueous acidified potassium dichromate(VI). The
reaction mixture was then boiled under reflux for one hour. The organic product was then
collected by distillation.
The yield of product was 75.0%.
What mass of product was collected?
A
1.989
B
2.079
C
2.709
D
4.809
w/11/qp11
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Fahad H. Ahmad (+92 323 509 4443)
14 Use of the Data Booklet is relevant to this question.
A significant contribution to atmospheric carbon dioxide levels comes from the thermal
decomposition of limestone, in the manufacture of cement and of lime for agricultural purposes.
Cement works roast 1000 million tonnes of limestone per year and a further 200 million tonnes is
roasted in kilns to make lime.
What is the total annual mass output of carbon dioxide On million tonnes) from these two
processes?
A
440
B
527
C
660
D
880
w/11/qp11
15 Use of the Data Booklet is relevant to this question.
A 5.00 g sample of an anhydrous Group II metal nitrate loses 3.29 g in mass when heated
strongly.
Which metal is present?
A
magnesium
B
calcium
C
strontium
D
barium
w/11/qp11
2
Use of the Data Booklet is relevant to this question.
Lead(JV) chloride will oxidise bromide ions to bromine. The Pb4+ ions are reduced to Pb2+ ions in
this reaction.
If 6.980 g of lead(IV) chloride is added to an excess of sodium bromide solution, what mass of
bromine would be produced?
A
0.7999
B
1.5989
C
3.1969
D
6.3929
w/11/qp11
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Page 12
Fahad H. Ahmad (+92 323 509 4443)
39 Use of the Data Booklet is relevant for this question.
In an organic synthesis, a 62 % yield of product is achieved.
Which of these conversions are consistent with this information?
1
74.00g of butan-2-ol � 44.649 of butanone
2
7 4.00g of butan-1-ol � 54.56 g of butanoic acid
3
74.00g of 2-methylpropan-1-ol � 54.569 of 2-methylpropanoic acid
w/10/qp12
14 Use of the Data Booklet is relevant to this question.
Which mass of solid residue can be obtained from the thermal decomposition of 4.10 g of
anhydrous calcium nitrate?
A
0.709
B
1.00g
C
1.409
0
2.259
w/10/qp12
15 Ammonium sulfate in nitrogenous fertilisers in the soil can be slowly oxidised by air producing
sulfuric acid, nitric add and water.
How many moles of oxygen gas are needed to oxidise completely one mole of ammonium
sulfate?
A
1
B
2
C
3
0
4
w/10/qp11
12 Camphor is a white solid which was used to make the early plastic celluloid. Camphor contains
the same percentage by mass of hydrogen and oxygen.
What is the molecular formula of camphor?
w/10/qp11
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Page 13
Fahad H. Ahmad (+92 323 509 4443)
5
Use of the Data Booklet is relevant to this question.
Nickel makes up 20 % of the total mass of a coin. The coin has a mass of 10.0g.
How many nickel atoms are in the coin?
A
2.05 x 1a22
B
4.30 x 1022
c
1.03 x 1023
D
1.20 x 1024
w/10/qp11
31
A monomer undergoes addition polymerisation. A 1 mol sample of the monomer is completely
polymerised.
How many moles of polymer might, theoretically, be formed?
1
1
2
10-6
3
1
6.02 x 1023
w/09/qp11
19 In an historically famous experiment Wohler heated 'inorganic' ammonium cyanate in the
absence of air. The only product of the reaction was 'organic' urea, CO(NH2)2. No other products
were formed in the reaction.
What is the formula of the cyanate ion present in ammonium cyanate?
A
CNO..
B
CN02..
c co-
D
NO..
w/09/qp11
2
0.200 mol of a hydrocarbon undergo complete combustion to give 35.2 g of carbon dioxide and
14.4 g of water as the only products.
What is the molecular formula of the hydrocarbon?
w/09/qp11
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Fahad H. Ahmad (+92 323 509 4443)
30 Use of the Data Booklet is relevant to this question.
Ethyl ethanoate can be obtained from ethanoic acid and ethanol by the following reaction.
Ethanol (30 g) and ethanoic acid (30 g) are heated under reflux together, and 22 g of ethyl
ethanoate are obtained.
What is the yield of the ester?
B
25%
A
38%
C
50%
D
n%
w/08/qp1
1
Use of the Data Booklet is relevant to this question.
Titanium(TV) oxide, Ti02, is brilliantly white and much of the oxide produced is used in the
manufacture of paint.
What is the maximum amount of Ti02obtainable from 19.0 tonnes of the ore ilmenite, FeTi03?
10.0 tonnes
A
B
12. 7 tonnes
C
14.0 tonnes
D
17.7 tonnes
w/08/qp1
2
Carbon disulphide vapour burns in oxygen according to the following equation.
A sample of 10 cm3 of carbon disulphide was burned in 50 cm3 of oxygen. After measuring the
volume of gas remaining, the product was treated with an excess of aqueous sodium hydroxide
and the volume of gas measured again. All measurements were made at the same temperature
and pressure, under such conditions that carbon disulphide was gaseous.
What were the measured volumes?
volume of gas
after burning/cm3
volume of gas after
adding NaOH(aq)/cm3
A
30
0
B
30
20
c
50
20
D
50
40
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Fahad H. Ahmad (+92 323 509 4443)
w/08/qp1
9
In an experiment, 50.0 cm3 of a 0.10 mol dm-3 solution of a metallic salt reacted exactly with
25.0 an3 of 0.10 mol dm-3 aqueous sodium sulphite.
The half-equation for oxidation of sulphite ion is shown below.
SOi (aq) + HiO(I) �SO! (aq) + 2W(aq) + 2eIf the original oxidation number of the metal in the salt was +3, what would be the new oxidation
number of the metal?
A
+1
B
+2
C
+4
D
+5
w/07/qp1
1
Use of the Data Booklet is relevant to this question.
'Nhen a sports medal with a total surface area of 150 cm2 was evenly coated with silver, using
electrolysis, its mass increased by 0.2169.
How many atoms of silver were deposited per cm2 on the surface of the medal?
A
8.0 x 1018
B
1.8x1019
c
1.2 x 1021
D
4.1 x 1022
w/07/qp1
14 A 5.00g sample of an anhydrous Group II metal nitrate loses 3.299 in mass on strong heating.
'Nhich metal is present?
A
magnesium
B
calcium
C
strontium
D
barium
w/06/qp1
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Page 16
Fahad H. Ahmad (+92 323 509 4443)
4
Samples of 10 cm3 of each of the first four members of the alkane series are separately mixed
with 70 cm3 of oxygen. Each is then burned and the total volume, V, of residual gas measured
again at room temperature and pressure.
Which graph represents the results that would be obtained?
A
V/cm3
B
j
V/cm3
j�
80
I
x- -
80
60
I/
60
40
20
-,- ,-.,-
0
x
x
x
x
->-->-
20
CH4
I/
-
__ ._
x
/
I
CH
3
CH4
8
C2Hs
C4H10
c
V/cm3
I/
0
I
I
40
x
x
I/
C3H8
C2Hs
C4H10
D
a
V/cm3
80
80
60
->-- >->--
60 -
x
40
I'
x ..
I'
x
x
0
I
I
>-->-->-
I
I
x- -
20
0
C3H8
C2Hs
x ... x
-x
40
20
CH4
>-->-
C4H10
CH4
C3H8
C2Hs
C4H10
w/06/qp1
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Page 17
Fahad H. Ahmad (+92 323 509 4443)
1
The amount of calcium ions in a sample of natural water can be determined by using an ionexchange column as shown in the diagram.
A 50 cm3 sample of water containing dissolved calcium sulphate was passed through the ionexchange resin. Each calcium ion in the sample was exchanged for two hydrogen ions. The
resulting acidic solution collected in the flask required 25 cm3 of 1.0 x 10-2 mol dm...J potassium
hydroxide for complete neutralisation.
What was the concentration of the calcium sulphate in the original sample?
A
2.5 x 1 o...J rnol dm...J
B
1.0 x 10-2 rnol dm-3
C
2.0 x 10-2 rnol dm...J
D
4.0 x 10-2 rnol dm...J
w/06/qp1
15 Use of the Data Booklet is relevant to this question.
What volume of oxygen, measured under room conditions, can be obtained from the thermal
decomposition of 8.2 g of calcium nitrate (Mr = 164 )?
A
150cm3
B
300cm3
C
600cm3
D
1200cm3
w/05/qp1
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Page 18
Fahad H. Ahmad (+92 323 509 4443)
1
The petrol additive tetraethyl-lead(IV), Pb(C2H5)4, is now banned in many countries. When it is
completely burned in air, lead(II) oxide, C02 and H20 are formed.
How many moles of oxygen are required to burn one mole of Pb(CzH5)4?
A
9.5
B
C
11
13.5
D
27
w/05/qp1
19 Ammonium sulphate in nitrogenous fertilisers in the soil can be slowly oxidised by air producing
sulphuric acid, nitric acid and water.
How many moles of oxygen are needed to oxidise oompletely one mole of ammonium sulphate?
A
1
B
2
C
3
D
4
w/04/qp1
3
The foul smell that skunks spray is due to a number of thiols, one of which is methanethiol,
CH3SH, which burns as follows.
A sample of 10 an3 of methanethiol was exploded with 60 cm3 of oxygen.
What would be the final volume of the resultant mixture of gases when cooled to room
temperature?
A
20cm3
B
30cm3
C
50an3
D
70cm3
w/04/qp1
22
On strong heating a hydrocarbon produces ethene, propane and but-t-ene in the mole ratio
5: 1 : 1.
What is the molecular formula of the hydrocarbon?
w/03/qp1
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Fahad H. Ahmad (+92 323 509 4443)
15
One mole of each of the following compounds is strongly heated and any gas produced is
collected at room temperature and pressure.
From which compound is 24 dm3 of gas likely to be collected?
[One mole of any gas occupies 24 dm3 at room temperature and pressure.]
D
Mg(OH)2
w/03/qp1
1
Use of the Data Booklet is relevant to this question.
Analytical chemists can detect very small amounts of amino acids, down to 3 x 10-21 mol.
How many molecules of an amino acid (Mr= 200) would this be?
A
9
B
200
C
1800
D
360000
w/03/qp1
2
Use of the Data Booklet is relevant to this question.
A garden fertiliser is said to have a phosphorus content of 30.0% 'P205 soluble in water'.
What is the percentage by mass of phosphorus in the fertiliser?
A
6.55%
B
13.1 %
C
26.2%
D
30.0%
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Page 20
Fahad H. Ahmad (+92 323 509 4443)
3
A sample of the hydrocarbon C6H12 is completely burned in dry oxygen and the product gases are
collected as shown.
[�: H, 1 ; C, 12; 0, 16.)
excess of 02
H20 + C02 + excess of 02
-----...
-----...
a
p
..
..........,.
anhydrous calcium
chloride
(to absorb H20)
The increases in mass of the collecting vessels P and
respectively.
a
sodalime
(to absorb C02)
of the apparatus are Mp and Ma,
What is the ratio Mp I Ma?
A
0.41
B
0.82
C
1.2
D
2.4
w/03/qp1
38 A number of alcohols with the formula C4H100 are separately oxidised. Using 70g of the alcohols
a 62 % yield of organic product is achieved.
What mass of product could be obtained?
1
42.2 g of butanone
2
51.6 g of butanoic acid
3
51.6 g of 2-methyl propanoic acid
s/12/qp11
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Fahad H. Ahmad (+92 323 509 4443)
14 Use of the Data Booklet is relevant to this question.
The reaction between aluminium powder and anhydrous barium nitrate is used as the propellant
in some fireworks. The metal oxides and nitrogen are the only products.
Which volume of nitrogen, measured under room conditions, is produced when 0. 783 g of
anhydrous barium nitrate reacts with an excess of aluminium?
A
46.8cm3
B
72.0cm3
C
93.6cm3
D
144cm3
s/12/qp11
23 The products obtained by cracking an alkane,
X. are methane, ethene and propane.
The mole fraction of ethene in the products is 0.5.
What is the identity of X?
B
CsH1s
s/11/qp12
11
0.144 g of an aluminium compound X react with an excess of water, to produce a gas. This gas
burns completely in Oz to form H20 and 72 cm3 of C02 only. The volume of C02 was measured at
room temperature and pressure.
What could be the formula of X?
[C = 12.0, Al= 27.0; 1 mole of any gas occupies 24 dm3 at room temperature and pressure]
s/11/qp12
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Fahad H. Ahmad (+92 323 509 4443)
10 Tanzanite is used as a gemstone for jewellery. It is a hydrated calcium aluminium silicate mineral
with a chemical formula Cai,Alx8iy012(0H).6Y:iHiO. Tanzanite has Mr of 571.5.
Its chemical composition is 14.04 % calcium, 14.17 % aluminium, 14.75 % silicon, 54.59% oxygen
and 2.45 % hydrogen.
(Ar values: H = 1.0, 0 = 16.0, AZ= 27.0, Si= 28.1, Ca= 40.1)
What are the values of x and y?
x
y
A
1
1
B
2
3
c
3
3
D
6
1
s/11/qp12
33 Use of the Data Booklet is relevant to this question.
Zinc reacts with hydrochloric acid according to the following equation.
Zn + 2HCl � ZnCl2 + H2
Which statements are correct?
(All volumes are measured at room conditions.]
1
A 3.27 g sample of zinc reacts with an excess of hydrochloric acid to give 0.050 mol of zinc
chloride.
2
A 6.54 g sample of zinc reacts completely with exactly 100 cm3 of 1.00 mo! dm-3 hydrochloric
acid.
3
A 13.08 g sample of zinc reacts with an excess of hydrochloric acid to give 9.60 dm3 of
hydrogen.
s/11/qp11
13 0.02 mol of aluminium is burned in oxygen and the product is reacted with 2.00 mol dm-3
hydrochloric acid.
What minimum volume of acid will be required for complete reaction?
A
15cm3
B
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20cm3
C
30cm3
D
60cm3
AS: Moles and Stoichiometry (MCQs)
Page 23
Fahad H. Ahmad (+92 323 509 4443)
s/11/qp11
35 In a car engine, non-metallic element X forms a pollutant oxide Y.
Further oxidation of Y to Z occurs in the atmosphere. In this further oxidation. 1 mol of Y reacts
with X mol of gaseous oxygen.
What can X be?
1
carbon
2
nitrogen
3
sulfur
s/10/qp11
9
Which mass of gas would occupy a volume of 3dm3 at 25°C and 1 atmosphere pressure?
(1 mol of gas occupies 24dm3 at 25°C and 1 atmosphere pressure.]
Oi
A
3.2g
gas
B
5.6g N2 gas
C
8.0g S02 gas
D
11.0 g C02 gas
s/10/qp11
8
Use of the Data Booklet is relevant to this question.
2.920 g of a Group II metal, X, reacts with an excess of chlorine to form 5.287 g of a compound
with formula XC[z.
What is metal X?
A
barium
B
calcium
C
magnesium
D
strontium
s/10/qp11
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Fahad H. Ahmad (+92 323 509 4443)
1
Use of the Data Booklet is relevant to this question.
In leaded petrol there is an additive composed of lead, carbon and hydrogen only. This
compound contains 29. 7 % carbon and 6.19 % hydrogen by mass.
What is the value of x in the empirical formula PbC8Hx?
A
5
B
C
6
16
D
20
s/09/qp1
2
A household bleach contains sodium chlorate{!), NaClO, as its active ingredient. The
ooncentration of NaClO in the bleach can be determined by reacting a known amount with
aqueous hydrogen peroxide, H202.
When 25.0cm3 of bleach is treated with an excess of aqueous l-ti02, 0.0350 mol of oxygen gas is
given off.
What is the concentration of NaClO in the bleach?
A
8.75 x 10'"4moldm..J
B
0.700 rroldrn?
C
0.875 mol dm-3
D
1.40 mol dm-3
s/09/qp1
31
For complete combustion, 1 mol of an organic compound X was found to require 2.5 mol of
molecular oxygen.
Which compounds could be X?
s/08/qp1
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Fahad H. Ahmad (+92 323 509 4443)
15 Use of the Data Booklet is relevant to this question.
The combustion of fossil fuels is a major source of increasing atmospheric carbon dioxide, with a
consequential rise in global warming. Another significant contribution to carbon dioxide levels
comes from the thermal decomposition of limestone, in the manufacture of cement and of lime for
agricultural purposes.
Cement works roast 1000 million tonnes of limestone per year and a further 200 million tonnes is
roasted in kilns to make lime.
What is the total annual mass output of carbon dioxide (in million tonnes) from these two
processes?
A
440
B
527
C
660
D
880
s/08/qp1
1
In the Basic Oxygen steel-making process the P4010 impurity is removed by reacting it with
calcium oxide. The only product of this reaction is the salt calcium phosphate, Ca3(P04)2.
In this reaction, how many moles of calcium oxide react with one mole of P4010?
A
1
B
1.5
C
3
D
6
s/08/qp1
2
Use of the Data Booklet is relevant to this question.
A typical solid fertiliser for use with household plants and shrubs contains the elements N, P, and
Kin the ratio of 15g: 30g :15g per 100g of fertiliser. The recommended usage of fertiliser is 149
offertiliser per 5 dm3 of water.
What is the concentration of nitrogen atoms in this solution?
A
0.03 mol dm-3
B
0.05 mol dm-3
C
0.42 mol dm-3
D
0.75 mol dm-3
s/08/qp1
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Page 26
Fahad H. Ahmad (+92 323 509 4443)
2
Use of the Data Booklet is relevant to this question.
Oxides of nitrogen are pollutant gases which are emitted from car exhausts.
In urban traffic, when a car travels one kilometre, it releases 0.23 g of an oxide of nitrogen NxOy,
which occupies 120 cm3.
What are the values of x and y?
(Assume 1 mol of gas molecules occupies 24.0dm3.)
A
x=1,y=1
B
x=1,y=2
c
x = 2, y = 1
0
x = 2, y = 4
s/07/qp1
16 Use of the Data Booklet is relevant to this question.
What mass of solid residue can be obtained from the thermal decomposition of 4.10 g of
anhydrous calcium nitrate?
A
0.70g
B
1.00g
C
1.40g
0
2.25g
s/06/qp1
1
N204 is a poisonous gas. It can be disposed of safely by reaction with sodium hydroxide.
What is the minimum volume of 0.5 mol dm-3 NaOH(aq) needed to dispose of 0.02 mol of N204?
A
8cm3
B
12.5cm3
C
40cm3
D
80cm3
s/06/qp1
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Fahad H. Ahmad (+92 323 509 4443)
36 The number of moles of chlorine that react with 1 mol of Xis twice the number of moles of
chlorine that react with 1 mol of Y.
Which of these pairs could be X and Y?
x
y
1
Mg(s)
Na(s)
2
�
KBr(aq)
3
cold NaOH(aq)
hot NaOH(aq)
s/05/qp1
18 In an historically famous experiment Wohler heated "inorganic" ammonium cyanate in the
absence of air. The only product of the reaction was "orqanic" urea, CO(NH2}z. No other products
were formed in the reaction.
What is the formula of the cyanate ion present in ammonium cyanate?
B
CN02-
c co-
D
NO-
s/05/qp1
2
On collision, airbags in cars inflate rapidly due to the production of nitrogen.
The nitrogen is formed according to the following equations.
How many moles of nitrogen gas are produced from 1 mol of sodium azide, NaN3?
A
1.5
B
1.6
C
3.2
D
4.0
s/05/qp1
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Fahad H. Ahmad (+92 323 509 4443)
1
A pure hydrocarbon is used in bottled gas for cooking and heating.
When 10 cm3 of the hydrocarbon is burned in 70 cm3 of oxygen (an excess), the final gaseous
mixture contains 30 cm3 of carbon dioxide and 20 cm3 of unreacted oxygen. All gaseous volumes
were measured under identical conditions.
What is the formula of the hydrocarbon?
s/05/qp1
18 Use of the Data Booklet is relevant to this question.
In the commercial electrolysis of brine, the products are chlorine, hydrogen and sodium
hydroxide.
What is the maximum yield of each of these products when 58.5 kg of sodium chloride are
electrolysed as brine?
yield of
chlorine I ko
yield of
hvdroqen I ko
yield of
sodium hydroxide I ko
A
35.5
1
40
B
35.5
2
40
c
71
1
40
0
71
2
80
s/04/qp1
9
Which substance, in 1 mol dm ·3 aqueous solution, would have the same hydrogen ion
concentration as 1 mol dm-3 of hydrochloric acid?
A
ethanoic acid
B
nitric acid
C
sodium hydroxide
D
sulphuric acid
s/04/qp1
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Page 29
Fahad H. Ahmad (+92 323 509 4443)
3
Use of the Data Booklet is relevant to this question.
Most modern cars are fitted with airbags. These work by decomposing sodium azide to liberate
nitrogen gas, which inflates the bag.
A typical driver's airbag contains 50 g of sodium azide.
Calculate the volume of nitrogen this will produce at room temperature.
A
9.2dm3
B
13.9dm3
C
27.7dm3
D
72.0dm3
s/04/qp1
2
Self-igniting flares contain Mg3P2. With water this produces diphosphane, P2H4, which is
spontaneously flammable in air.
Which equation that includes the formation of diphosphane is balanced?
A
Mg3P2 + 6H20 � 3Mg(OH)2 + P2H4
B
Mg3P2 + 6H20 � 3Mg(OH)i + P2H4 +
C
2Mg3P2 + 12H20 � 6Mg(OH)2 + P2H4 + 2PH3
D
2Mg3P2 + 12H20 � 6Mg(OH)2 + 3P2H4
Hi
s/04/qp1
1
Which of these samples of gas contains the same number of atoms as 1g of hydrogen
(Mr: H2, 2)?
A
22g of carbon dioxide (Mr: CO:z, 44)
B
8 g of methane (Mr:
C
20g of neon (Mr: Ne, 20)
D
8 g of ozone (Mr: 03, 48)
c�. 16)
s/04/qp1
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Page 30
Fahad H. Ahmad (+92 323 509 4443)
28
In its reaction with sodium, 1 mol of a compound X gives 1 mol of H2(g).
Which compound might X be?
A
CH3CH2CH2CH20H
B
(CH3hCOH
c
CH3CH2CH2C02H
D
CH3CH(OH)C02H
s/03/qp1
1
The use of the Data Booklet is relevant to this question.
What is the number of molecules in 500 cm3 of oxygen under room conditions?
x 1022
A
1.25
B
1.34 x 1022
C
3.0
x 1o22
D
3.0
x 1026
s/03/qp1
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Page 31
Fahad H. Ahmad (+92 323 509 4443)
Marking Scheme
6-C
8-D
29-D
6-A
15-B
3-B
12-C
8-D
10-D
17-A
9-B
14-D
19-A
40-A
18-B
10-C
12-A
18-A
27-A
13-A
26-A
2-C
11-B
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16-D
26-C
34-B
25-A
9-D
17-D
15-B
26-A
4-C
2-A
25-C
14-B
15-B
2-C
39-A
14-C
15-D
12-C
5-A
31-C
19-A
2-D
30-C
1-A
2-C
9-B
1-A
14-B
4-D
1-A
15-C
1-C
19-D
3-C
22-B
15-B
1-C
2-B
3-A
38-A
14-B
23-B
11-C
10-C
33-D
13-C
AS: Moles and Stoichiometry (MCQs)
35-C
9-C
8-D
1-D
2-D
31-C
15-B
1-D
2-A
2-B
16-C
1-D
36-B
18-A
2-B
1-C
18-A
9-B
3-C
2-B
1-C
28-D
1-A
Page 32